I use a gmapsupp.img generated with a reduced style derived from the default mkgmap-style . Routing for cars works fine, if the routes are short. But if I try to plan a long journey (1000 km). The route calculation gets stuck for some minutes at lets say 80 percent and finally comes to a result. But the resulting route is something that looks like a concatenation of beelines. My assumption is, that Nüvi contains an overview map of the world (or Europe) that I cannot disable. Could I replace it using --tdbfile in mkgmap? But the option mentions MapSource, I tried to avoid MapSource for now.

Routing works fine, if I disable Motorways (or toll roads), but the route seems to be somewhat inconvenient.

Perhaps my questions is a little bit outdated, since there are good smartphone based apps for navigation. But I love my old fashioned Nüvi. This leads to the next question: Is there a chance that there will be TMC information compiled into mkgmap maps sometimes in the future? As far as I understand, nobody knows where it is stored inside encrypted proprietary maps.

Best regards
Bodo